- In a large bowl, combine flour, snipped rosemary, salt, garlic powder, and white pepper. Using a pastry blender, cut in butter until pieces are pea-size. Add Asiago cheese; toss well. Drizzle milk over flour mixture; gently toss with a fork.
- Drop small dollops of sour cream over flour mixture. Using a wooden spoon, stir until dough comes together and forms a ball.
- Turn dough out onto a lightly floured surface. Divide dough in half. Using your hands, roll each dough half back and forth, from center to edges, to form a 6-1/2-inch-long log about 1-1/2 inches in diameter.
- Place one log along the bottom edge of a piece of waxed paper or parchment paper. Roll up paper and dough log. If needed, continue to roll log back and forth to create an even shape from end to end. Repeat with second log. Chill for 24 to 48 hours.
- Preheat oven to 325 F. Lightly grease a baking sheet; set aside. Unwrap logs. Using a sharp serrated knife, cut logs into 1/8- to 1/4-inch-thick slices. Place slices 1/2 inch apart on prepared baking sheet. If desired, dip rosemary leaves in egg whites and place in the centers of the slices.
- Bake for 18 to 22 minutes or until golden (do not overbrown the edges). Transfer to a wire rack and cool. Makes about 54 crackers.
From the Test Kitchen
Prepare as directed through Step 4. Wrap logs in foil and freeze for up to 2 months. To serve, thaw for 30 to 60 minutes before slicing. Continue as directed in Step 5.
Prepare and bake as directed. Layer cooled crackers between sheets of waxed paper in an airtight container; cover. Store at room temperature for up to 3 days.